Microstructural, magnetotransport, and electronic subband studies of InAs xP 1− x/InP modulation-doped strained single quantum wells

Abstract

The microsturctural properties in lattice-mismatched InAs 0.3P 0.7/InP modulation-doped single quantum wells were investigated by using transmission electron microscopy (TEM) and the Raman scattering spectroscopy measurements, and the low-temperature magnetotransport properties of the two-dimensional electron gas (2DEG) in the InAs 0.3P 0.7 wells were studied using Shubnikov–de Haas (S–dH) and Van der Pauw Hall-effect measurements. The TEM measurement on the InAs 0.3P 0.7/InP single quantum wells showed that the InAs 0.3P 0.7 active layer was grown pseudomorphologically on the InP buffer layer in spite of the lattice mismatch. The values of the horizontal, the vertical strains and the horizontal stress of the InAs 0.3P 0.7 layer were −9.6×10 3, 1.07×10 −2, and −8.67×10 −2 dyne cm −2, respectively. A possible crystal structure for the InAs 0.3P 0.7/InP single quantum well is presented on the basis of the TEM results. The S–dH measurements and the fast Fourier transformation results for the S–dH data clearly indicate electron occupation of one subband in the InAs 0.3P 0.7/InP single quantum well. The carrier density and the effective mass of the 2DEG as determined from the S–dH measurements were 5.71×10 11 cm −2 and 0.06256 m 0, respectively. The electronic structures in the quantum wells were calculated by using a self-consistent method. These present results can help improve the understanding of potential applications of modulation-doped InAs x P 1− x /InP strained single quantum wells in high speed electronic devices.